From Pathfinder Lost Omens Cheliax, Infernal Inheritance, which isn't enabled.

Glimpse the Netherworld

FOCUS 4

UNCOMMON COLD CONCENTRATE FOCUS MANIPULATE SHADOW

Cast

Range 60 feet

Area 10-foot emanation

Defense basic Reflex

Trigger A living enemy you can see within 60 feet is reduced to 0 Hit Points.

As a creature slips into that final darkness, you tear through the fabric of reality to release the shadows of the Netherworld. Each creature in a 10-foot emanation from the triggering enemy takes 4d8 cold] damage with a basic Reflex save. On a failure, a creature also takes (the item's level − 3)d6 persistent cold damage (double on a critical failure).

Heightened (+1) Increase the cold damage by 1d8 and the persistent cold damage by 1d6

Pathfinder Lost Omens Cheliax, Infernal InheritanceORC